Which of the following is not a reason for the irreversibility of chemical reactions in cells?

a. Chemical reactions that release energy would
require energy to be reversed.
b. A product might be continually removed from the
reaction site.
c. Biological reactions can only proceed in a
single direction.
d. A product might be expelled from the body.

a. Twisting and bending to form a more complex
structure such as a helix
b. Two or more polypeptide chains aggregated to
form a complex protein
c. The linear sequence of amino acids
d. α-helical or β-pleated regions of the
polypeptide chain folded upon one another

d. α-helical or β-pleated regions of the
polypeptide chain folded upon one another

25

A substance that dissociates into cations and hydroxyl ions is __________.

a. an acid
b. a base
c. a salt
d. an electrolyte

b. a base

26

Which substance is the primary energy-transferring molecule in the cell?